Our goal is to develop and evaluate better transducers for improving the quality of ultrasonic biomedical images. Improved transducers will be developed using new linear piezoelectric ceramic/polymer composite materials and new nonlinear materials not previously evaluated for medical ultrasound transducers. This is a collaborative effort between a well established piezoelectric ceramics producer, Honeywell, and a well established biomedical imaging laboratory at Mayo Clinic. Honeywell will provide and characterize the physical/acoustic properties of a wide range of new ceramic/polymer composite transducer elements having attributes predictive of good biomedical imaging. In addition, Honeywell will provide elements fabricated from several nonlinear materials which may result in transducers that will detect magnitude or power of received ultrasound energy. The Mayo group, in collaboration with the Honeywell group, will assemble the composite elements into concave disc and linear array transducers, and will characterize their imaging responses, in terms of resolution cell size and their sensitivities, in terms of transmit and receive characteristics such as gain bandwidth product, transmit sensitivity factor, insertion loss and quality factor using calibrated hydrophones. Relationships between the transducer element physical/acoustic properties, the imaging properties, and the sensitivity measurements will be developed and used to predict the behavior of new transducers. Successful completion of this project would result in 1) better and more easily fabricated transducers for biomedical imaging and 2) nonlinear transducers for measurement of magnitude or power of ultrasonic beams.